/*
 * Copyright (C) 2016 AriaLyy(https://github.com/AriaLyy/Aria)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.arialyy.aria.core.group;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 子任务重试队列
 */
final class SimpleSubRetryQueue {
  private volatile static SimpleSubRetryQueue INSTANCE = null;
  private ExecutorService pool = new ThreadPoolExecutor(5, 100,
      60L, TimeUnit.SECONDS,
      new SynchronousQueue<Runnable>());

  public synchronized static SimpleSubRetryQueue getInstance() {
    if (INSTANCE == null) {
      synchronized (SimpleSubRetryQueue.class) {
        INSTANCE = new SimpleSubRetryQueue();
      }
    }

    return INSTANCE;
  }

  private SimpleSubRetryQueue() {

  }

  void offer(AbsSubDLoadUtil subDLoadUtil) {
    pool.submit(subDLoadUtil.getLoader());
  }
}
